The invention relates to a vision enhancing system that provides magnification capabilities while presenting an aesthetically pleasing appearance. Although the invention has other applications, it is primarily to enable low-vision persons to read fine print material, to see blackboard work in educational facilities, and, in general, to provide acceptable distance vision.
There are a large number of low-vision persons, i.e., those having about 20/200 vision. The visual acuity of such individuals is not correctable to better than 20/50 with single-lens systems such as conventional eyeglasses or contact lenses: correction to 20/100 being more typical. Various attempts to enhance the visual acuity of such individuals to 20/20 have resulted in the construction of unsightly and unwieldy optical structures extending forward from the individual's eyes. While such prior attempts were optically effective, the forward extension of the optics provided an awkward impediment to head movement and the weight, being well forward of the nose support, created an unnatural muscular strain.
According to the present invention, apparatus is provided that is capable of correcting the visual acuity of low-vision persons without the drawbacks inherent in prior art attempts. The apparatus according to the present invention is eminently suited for use with conventional eyeglasses, extends no significant distance forward from the eyeglasses, and in fact does not look substantially different from conventional eyeglasses. The system has a small weight (i.e., about 2 ounces or less), is safe and rugged, yet is capable of correcting a low-vision person's sight to 20/20, or close to it. Magnifications on the order of 4X to 8X are readily provided. Utilizing the system according to the present invention, a low-vision person is not immediately identified as such, and thus the system according to the present invention may be utilized without undesirably increasing the self-consciousness of the wearer.
A typical low-vision person has one dominant eye, and the preferred embodiment according to the present invention provides a monocular system for aiding the vision of the dominant eye of the low-vision wearer. However, the invention also has applicability to other than low-vision systems. For instance the basic apparatus according to the present invention may be modified for use in covert surveillance, spectating at sports and cultural events, etc., in either a monocular or binocular form.
According to the present invention, a vision-enhancing apparatus is provided that takes advantage of the distance between the wearer's temples to provide the major optical path, instead of extending it forward from the eyes of the user. By making the optical path parallel to a line between the wearer's temples, it is possible to obtain sufficient magnification while minimizing interference with the user's normal activities and the cosmetic drawbacks normally associated with vision-enhancing systems.
According to one aspect of the present invention, a prismatic telescopic arrangement is provided which includes an elongated casing with a light entry on the side at one end directed forward and a light exit on the opposite side of the casing at the other end directed toward the eye. A prismatic telescopic lens system including an objective, an ocular, and inverting and reversing optical means is mounted within the casing, so that light entering the casing through the light entry is directed down the length of the casing through the lens system and then directed out the light exit. Means are provided for adjusting the focus of the lens system, and means are provided for mounting the objective within the casing so that the majority of the focal length of the objective lies within, and parallel to the direction of elongation, of the casing. Means are provided for mounting the casing on a wearer's head so that the direction of elongation of the casing extends substantially horizontally across the wearer's forehead with the light exit at the wearer's eye. The mounting means preferably comprises an eyeglass frame including a support, nosepiece and ear pieces, with eyeglass lenses disposed in the frame support. Means are provided for mounting the casing on top of the frame support above the lenses and between the ear pieces, with the light entry and eyepiece disposed so that by tilting his/her eyes upward, the wearer can look through the light exit. The casing may be sealed so that dirt, moisture, and the like cannot enter the casing and affect the lens system, and the lens system itself may take a variety of forms depending upon the particular use. While a monocular system is preferred (especially for low-vision systems), a binocular system may be provided consisting of a pair of light entries and light exits into and from the casing, a pair of prismatic telescopic lens systems, a pair of adjustment means, and a pair of objective mounting means.
The apparatus according to the present invention also may be described with respect to the orientation of the first optical element of the lens system within the casing, which redirects light entering from the light entry. The mounting means for mounting the casing on the wearer's head so mounts the casing that the path of light exiting the first optical light redirecting element is substantially horizontal when the wearer is upright, and extends substantially parallel to a line between the wearer's temples, and preferably so that the path of light exiting the first optical light redirecting element is disposed in a substantially horizontal common plane with light in a path entering the light entry when the wearer is upright.
According to another aspect of the present invention, a sight-facilitating apparatus is provided comprising an eyeglass frame including a support, nosepiece, and ear pieces with eyeglass lenses disposed in the eyeglass frame support. An elongated casing including a lens system with an objective and an ocular, with the ocular mounted at one face of the casing, is provided, along with means for mounting the casing on top of the eyeglasses frame support so that the ocular is mounted directly above an eyeglass lens and on the same side of the frame support as the ear pieces. The casing is elongated in a first dimension and shortened in second and third dimensions, the mounting means mounting the casing so that its first dimension extends along the frame support between the ear pieces with the second dimension significantly less than the height of the eyeglass lenses and the third dimension roughly comparable to the second dimension, so that no obtrusive extension of the casing past the eyeglass frames from the wearer's head is provided. The light entry and light exit are disposed on opposite portions of the casing and are spaced in the first dimension a distance greater than the spacing between the pupils of the wearer's eyes. The casing with lens system disposed therein weighs about 2 ounces or less (e.g., 11/2 ounces) and is readily capable of providing magnifications of about 4X to 8X. For facilitating fitting of various individuals, the casing may comprise a plurality of detachable modular components.
It is the primary object of the present invention to provide a vision-enhancing device that is aesthetically pleasing yet is capable of readily providing desired magnification, especially for low-vision persons. This and other objects of the invention will become clear from the detailed description of the invention, and from the appended claims.